Rehabilitation of pipelines and passageways with a flexible liner using an inflatible bladder

ABSTRACT

An assembly which can be inserted into a pipeline or passageway on which a curable resin impregnated flexible lining is placed about an inflatable bladder is provided. The bladder is mounted to one end of a core pipe and folded over on itself. Medium flowing in the pipeliner passageway can pass through the core pipe during a lining operation. The core pipe is of sufficiently rigid nature to withstand inflation pressure to move the lining tube into the pipeliner passageway surface by inflation of the bladder, but yet is sufficiently flexible and bendable so as to bend enabling it follow curbs and falls in the pipeliner passageway into which it is inserted. Temporary holding means restrain the liner during insertion.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to the lining of pipelines or passageways.

2. Description of the Prior Art

This invention relates to the lining of pipelines or passageways, usingmaterials which are now referred to as "cured in place" materials.Specifically, "cured in place" materials comprise flexible lining tubesincluding absorbent materials such as fibrous felts, e.g. polyesterfelts which are impregnated with curable synthetic resin such aspolyester or epoxy. Whilst the lining tube is still flexible and is soimpregnated, it is held by fluid (liquid and/or gas) pressure againstthe surface of the pipeline or passageway to be lined, so that itconforms to the surface shape of the pipeline or passageway, and whilstso held it is caused to become hard or rigid by curing of the saidsynthetic resin. The method of curing may be any of a number of methodsincluding curing by heat, curing by radiation such as ultra violetradiation, or curing by ultrasonics. When heat is used the inflatingmedium may be heated whilst in the case of light cure and ultrasoniccure resins, an appropriate light or ultrasonic source As pulled throughthe applied lining tube. Some resins such as epoxy resins curenaturally, and are referred to as ambient curing resins, and these maybe used if required.

Various methods as disclosed An U.S. Pat. Nos. 4,064,211 and 4,009,063have been proposed for curing "cured in place" systems, including thatthe lining tube, having been pre-impregnated, may be everted into thepipeline or passageway, or alternatively may be pulled into the pipelineor passageway and then inflated, for example by means of an evertingmembrane. Arrangements have been suggested for effecting theimpregnation of the lining tube whilst it is in or whilst it is movinginto the pipeline or passageway to be cured as disclosed in U.S. Pat.No. 4,602,974.

Generally speaking, the known methods comprise inserting the lining tubeinto the pipeline or passageway so as to cover the surface of thepipeline or passageway between respective access points of the pipelineor passageway, such access points comprising for example accessmanholes, but frequently complete lining of the pipeline or passagewaybetween man-holes is not necessary, as for example it may be the casethat only a section of a pipeline or passageway has a defect or is in apoor state of repair such as to require relining by a "cured in place"method. The present invention is devoted to the provision of a systemand method for the lining of a section of a pipeline or passageway.

There have been proposals for repairing sections of undergroundpipelines or passageways using "cured in place" lining tubes, and onesuch proposal is disclosed in U.S. Pat. No. 5,044,405 wherein a lengthof the impregnated lining tube is carried inside a flexible carriertube. The carrier tube is in turn located inside an outer tubularcasing, and the entire assembly is located in position inside thepipeline or passageway having the section to be lined. The interior ofthe casing is pressurized in order to evert the carrier tube and with itthe lining tube out of the end of the casing and into fluid pressurecontact on the section of pipeline or passageway to be lined. Thepressure is maintained whilst the resin is caused to cure by anysuitable method, and then the carrier tube and and casing are detachedfrom the lining tube leaving the cured lining tube in position liningthe appropriate section of the pipeline or passageway. The use of thecarrier tube and casing make the method somewhat complicated as manysteps are to be carried out An order to create the assembly which isinserted in the pipeline or passageway.

The present invention provides a simpler method of installation byarranging that an inflatable bladder as the lining tube applied to theoutside thereof, and in this connection is might be mentioned that thelining tube may be a continuous tube when view in cross sectionalelevation, or it may be a tube formed by a flat web wrapped round thebladder with the meeting edges overlapped. In some cases it isadvantageous to overlap the lining tube in this way because then thelining tube need not be critically matched to the pipeline or passagewayinner diameter as it will take up the correct diametrical dimension asthe bladder is inflated and the degree of overlap of the edges of thelining tube will vary.

Patent specification WO 90/12243 does disclose that it is known toprovide a core member around which is an inflatable bladder, and thelining tube is applied over the bladder so as to be inflated by thebladder into contact with the pipeline or passageway surface, but thecore member in connection with that proposal is made up of a number ofrigid sleeves which are tensioned together by means of steel cableswhich pass through apertures in the sleeves. The sleeve ends areconfigured so as to be complimentary and to interfit whereby the lengthof the core member can be varied as required.

A disadvantage of that arrangement is that the core member by itsconstruction inhibits the feeding of the assembly the pipeline orpassageway, because pipelines or passageways often have bends and curvesand the lining and bladder are relatively delicate items which ifdragged against for example the surface of an underground pipeline orpassageway which is in the form of a sever, could well tear and fracturethese components,

SUMMARY OF THE INVENTION

The present invention is concerned with providing an arrangement whereinan assembly including a core member and inflatable bladder with a "curedin place" lining tube thereon can be effectively positioned in anunderground pipeline or passageway.

In accordance with the present invention, in a first aspect, a method oflining a section of a pipeline or passageway by a "cured in place"system comprises providing a length of lining tube which is impregnatedwith a curable synthetic resin and carrying that lining tube on anassembly including an annular inflatable bladder to the inside of whichis provided a core tube, transporting the assembly to the section ofpipeline or passageway to be lined, inflating the annular inflatablemember to press the length of lining tube to said section of thepipeline or passageway and effecting the cure of same, the said coretube being a flexible unitary continuous hollow tube of sufficientrigidity to support the air pressure and of sufficient bendability toenable it to bend round curves and corners around which the assemblymust pass in travelling along the pipeline or passageway to saidsection.

In this connection, the core or central tube, although having rigidity,in fact is of a semi-rigid construction such that it can bend slightlyso as to follow the curvature of the pipeline or passageway, and also isof sufficient hoop stress to withstand an internal vacuum, because in apreferred arrangement the tube serves as a means for applying a vacuumto the assembly in order to hold the length of lining tube and theannular inflation member in collapsed condition whilst the assembly isintroduced into the pipeline or passageway. Typically the rigid tubemaybe a rigid rubber like material of sufficient thickness to meet thecharacteristics indicated above.

By virtue of providing the assembly with the central rigid tube,arrangements can be made such that several assemblies can be provided onthe tube and can be applied to different sections of the pipeline orpassageway simultaneously, and if the pipeline or passageway hasnormally accommodates liquid flowing medium, the medium can continue toflow through the tube whilst the assembly is being inserted and curingis taking place.

The present invention also provides an assembly for introduction into apipeline or passageway, said assembly comprising a core tube surroundedby an annular inflatable bladder, said core tube being of sufficientrigidity to support the bladder when inflated without collapse of thecore tube and also being of sufficient bendability to enable it to bendaround curves in the pipeline or passageway into which it is inserted.

The core tube may be connected by one of its ends only to the bladderwhich may also be tubular formed with an inner side and an outer sidebut which sides are integrally connected at one end of the bladder. Thisconstruction provides that the core tube may be moved into and out ofthe bladder which action causes the bladder to evert and invert in thenature of a rolling pig which means that the inner side and outer sidechange positions when the assembly is fed into the pipeline orpassageway the core tube is inside the bladder and for the purposes ofclarity of explanation the terms "inner side" and "outer side" asapplied to the bladder mean the inner side and outer side in relation tothe core tube when the core tube is inside the bladder.

To construct the unit comprising the assembly and lining tube to beinserted in the pipeline or passageway, a length of the lining tube dulyimpregnated may have the bladder introduced thereinto by rolling thebladder inside out upon itself, and at the same time introducing thecore tube into the central region of the pig. In this connection thebladder may communicate with a pressure hose contained inside the coretube whereby air for inflating the bladder may be provided.

The unit is constructed above ground, and then is introduced into thepipeline or passageway for subsequent inflation, the unit having thebendability of the core enabling it to be fed down manholes and alongthe pipeline or passageway.

To the outside of the length of lining tube there may be provided a filmencasing the lining tube, and which also serves as a means enabling thecreation of a vacuum inside the film thereby to collapse the assemblyonto the core tube, and there may be an aperture in the central coretube enabling the vacuum to be created inside the external film.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described, by way ofexample, with reference to the accompanying diagramatic drawings,wherein;

FIG. 1 is a sectional side view inside a sewer pipe having a section tobe lined and shows a lining tube and assembly in accordance with anembodiment of the invention;

FIG. 2 is a view similar to FIG. 1, but showing the assembly bladder ininflated condition;

FIG. 3 is a view similar to view 1, but showing the lining tube afterthe resin thereof has been cured.

FIG. 4-7 show the method of assembling the arrangement of FIG. 1;

FIG. 8 is a diagram showing the introduction of the assembly of FIG. 1into the pipe and also showing how the centre portion of the assembly isextracted upon completion of the curing;

FIG. 9 shows an arrangement similar to FIG. 7 when in the FIG. 7condition;

FIG. 10 shows the arrangement of FIG. 9 when the bladder is collapsed;

FIG. 11 shows a transporter for the arrangement of FIG. 10 to enable itto be transported into the sewer;

FIG. 12 shows the arrangement of FIG. 10 when carried by the transporterof FIG. 11 and having transporting lines connected thereto; and

FIG. 13 is a sectional elevation of the arrangement of FIG. 12 taken onthe line A--A of FIG. 12

DETAILED DESCRIPTION

Referring to the drawings, and firstly to FIG. 1, a length of sewer pipe(10) to be lined with a length of cured in place lining tube is shown ashaving imperfections (12) giving rise to the reason for the liningoperation. It is assumed that the remainder of the pipe Is otherwisesound, and complete relining of the pipe is therefore inappropriate.

In register with the section (10) to be lined is shown a unit (14) whichcomprises a tubular construction having a central core tube or pipe (16)of hard rubber to the like of sufficient rigidity to withstand aninflation pressure and internal vacuum which as will be explained isapplied thereto, but is bendable so as to be capable of following anybends or curves in the pipe (10) as the unit (14) is fed thereinto, aswill be explained. The pipe (16) may be of corrugated construction andhave internal reinforcing and circumferentially extending metal wires inthe corrugations so that it can function as described above.

Surrounding the pipe (16) Is an annular inflation bladder (18) Offlexible plastics material, and formed in an endless arrangement in thattubular bladder (18) is defined by a length of tubular flexible andinflatable material turned inside upon itself, so that its ends asindicated by (20) and (22) are sealingly anchored to the tube (16) atone end only so as to form an annular pocket which can be inflated bymeans of an air pressure hose (24) and in particular an outlet (26)thereof which opens into the chamber created by the inflation memberbetween the said ends (20) and (22).

The tube (18) may for example be of a silicone material so that it canbe removed from the assembly after the inflation operation as will bedescribed.

Surrounding the annular tubular bladder (18) is the length of liningtube (28) which comprises suitably a tube or overlay of felt materialwhich is impregnated thoroughly with a curable synthetic resin. The feltmay typically be of polyester fibres, and a polyester resin may be usedfor the impregnation. Other felts and mixtures and other resins can beused.

Surrounding the felt layer (28) is a shrouding tubular film (30) tocomplete the unit.

In the condition of FIG. 1, the assembly is in flexible but collapsedcondition, to enable it to be fed into the pipe (10) so that there is infact as shown a substantial clearance between the shroud (30) and thesurface of the pipe (10). This arrangement is achieved in that a vacuumis drawn through an aperture (32) in the pipe (16) which leads to theinside of the shroud (30), but to the outside of the inflation bladder(18) thereby by drawing the assembly tightly onto the pipe (16). To thisend sealing tapes may be applied to the ends of the shroud (32) toprevent vacuum leaks.

When the unit is in position, as shown in FIG. 2 the vacuum inside thepipe (16) is removed, and the interior of the inflation bladder (18) ispressurised so as to blow up the lining tube length (28), to cause it tobe forced to the surface of a pipe (10), as shown clearly in FIG. 2.Whilst in this condition the resin is allowed to cure or is caused tocure by some initiation means such as heat, light, ultrasonics or thelike, and after curing takes place, the pipes (16) and the inflationbladder (18) are withdrawn leaving the cured resin lining (28) in placeas shown in FIG. 3. FIG. 4-7 illustrate how the assembly (14) is puttogether, and it will be seen than initially from FIG. 4 the lining tubelength (28) with its shroud (30) is arranged end to end with theinflation bladder (18), from which has been pulled core pipe (16) sothat it is arranged end to end with the pipe (16). The right hand end ofthe inflation tube (18) is introduced into the interior of the liningtube length (28), and the right hand end of the pipe (16) is inside theleft hand end of the inflation tube (18).

It is now simply a matter of inflating the inflation tube (18) forexample to a low pressure in the order of 5 p.s.i. as shown in FIG. 5and then the inflated member (18) is evened into the lining tube (28),by progressively pushing the pipe (16) into the interior of theinflation tube (18) as shown in FIG. 6, (the lining tube being held byhand pressure if necessary) until the arrangement indicated in FIG. 7 isreached. The pressure is removed from the inflation tube (18), and thenvacuum is applied through the port (32), to cause the assembly tocollapse to the FIG. 1 condition.

FIG. 8 shows that the assembly (14) can be introduced by means of atraction apparatus (36) with a vacuum coupling (38) from a ground leveltrailer (40), there being appropriate air hoses (42) connected throughthe central pipe (16) of the assembly to enable the inflation anddeflation of the assembly inflation bladder (18) as described above forthe completion of the insertion.

FIG. 8 shows that the unit marked `U` can be fed down a manhole `M` andfed into the pipe.(10) bending as it turns from the manhole `M` into thepipe (10), without collapse of the core tube (16), which is an importantaspect of the present invention. This bendability of the unit `U` isalso important when the unit lies to transverse underground pipes whichcurve as it is important not to have heavy frictional forces on the unit`U` as it is travelling along the pipe (10).

An effective means is therefore provided for positioning and applying alength of lining tube of a "cured in place" type to a specified sectionof a pipeline. The positioning of the assembly (14) may take place byany conventional means such as by the use of a television camera, or byarranging for some pre-determined datum to be established and inrelation to which the assembly (14) is positioned, but such positioningmethod is not part of the present invention.

Referring now to FIGS. 9-13, which show an alternative embodiment of theinvention, the assembly shown is constructed and operates in the sameprinciple as already described in relation to the previous embodiment,but includes a number of modifications which also can be included in theembodiment of FIGS. 1-8. The unit shown in FIGS. 9-13 is put in place inthe manner already described in relation to the previous figures.

Referring to these drawings, in FIG. 9, the unit shown is in theposition corresponding to the position shown in FIG. 7 for thepreviously described unit, and similar reference numerals are used inrelation to the equivalent parts already described in relation to theprevious figures. Thus, the lining tube is indicated by reference 28,and it is shown as being supported on the inflated bladder (18) which inturn receives centrally thereof the core pipe (16). The core pipe (16)has enlarged ends (16A) which may be formed by shaping the pipe ends orby adding thereto enlargement rings or the like. These ends (16A)stabilize the pipe inside the inflated bladder (18), and if suchenlargement (16A) are not provided, there can be a tendancy for the corepipe (16) to be held by the bladder in a slightly unstable manner suchthat the merest force might cause the pipe (16) to be ejected from thebladder as the bladder rolls upon itself. The enlarged ends inhibit thisdifficulty.

In collapsing the bladder (18) from the FIG. 9 position the FIG. 10position, any suitable arrangement may be adopted such as by simplyexhausting the air inside the bladder or by positively withdrawing itthrough suitable means. For example the air may be withdrawn throughpipe (24) which also serves as the air pressure pipe.

When the bladder is collapsed, the bladder and the lining (28) are thenfolded around the core pipe (16) as shown in FIG. 10, and the meetingedges of the lining tube (28) are temporarily held by means of adhesivetapes (30) applied across the meeting edges as shown. The assembly inthe condition shown in FIG. 10 is inserted into the pipeline orpassageway by being carried on a transporter (32) which resembles ahammock and is made of a sheet of flexible material such as a reinforcedplastic sheet. The ends of the hammock transporter (32) are connected topull ropes (34) and (36) by which the assembly can be inserted in thepipeline or passageway.

FIG. 12 shows that the hammock transporter (32) after it receives theunit of FIG. 10 is wrapped around the sides of the unit and furthertemporary adhesive holding patches (38) are applied across thetransporter edges and the adjacent bladder and lining tube as shown inFIG. 12.

FIG. 12 also shows the air line (24), and at the other end of theassembly the guide ring (40) Which passes through an aperture (42) inthe end (16A) of core pipe (16) so that an extension of rope (34) in theform of a slip rope (42) can pass therethrough as shown.

FIG. 13 shows the arrangement of FIG. 12 in sectional elevation.

The assembly of FIG. 12 is pulled into the underground pipeline orpassageway in the direction of arrow (44) by pulling on ropes (34) and(42), the rope (36) serving as a hold back means in order to control thein feed of the assembly into the pipeline or passageway. Positioning ofthe assembly of FIG. 12 inside the pipeline or passageway is again byany suitable means such as a television camera, and the entire assemblyshown in FIG. 12 as the bendability hereinbefore referred to enablingsmooth positioning of the assembly with minimal damage due to frictionon the components of the assembly as it travels around curved sectionsof the pipeline or passageway. In this connection, the slip rope (42)serves to prevent the assembly of FIG. 10 from slipping relative to thehammock transporter (32) should the unit rub against the pipeline orpassageway walls in its travel to its final position.

When the unit is in its final position, rope (34) is pulled whilst airline (24) is held, so that the transporter (32) separates from theassembly of FIG. 10, such assembly remaining in the correct position.During this separation, the slip rope (42) is allowed to slip throughring (40) and it will also be separated from the assembly. Hold backrope (36) travels with the transporter (32), and therefore is removedfrom the pipeline or passageway leaving the assembly in the correctposition. It is to be mentioned that during this separation operation,the adhesive patches (38) yield due to the separating forces.

It is now simply a matter of inflating the bladder (18) to break theholding effect of the tapes (30) and to allow the assembly to inflate tothe condition shown in FIG. 9 and also as shown in FIG. 2 cured by thelining tube is applied against the surface to be aligned and theprocedure is similar to that already described in relation to theprevious figures.

The core pipe (16) and the bladder (18) are removed by pulling on theair line (24) to pull out the core pipe and to invert the bladder (18)and to peel it away from the cured lining tube leaving the condition asshown in FIG. 3.

By the provision of the central rigid pipe (16), simultaneous inflationof a number of assemblies inside the pipeline may be effected.

What is claimed is:
 1. A method of lining a section of a pipeline orpassageway by a "cured in place" system comprising providing a length oflining tube which is impregnated with a curable synthetic resin andcarrying that lining tube on an assembly including an annular inflatablebladder to the inside of which is provided a core tube, transporting theassembly to the section of pipeline or passageway to be lined, inflatingthe annular inflatable bladder to press the length of lining tube tosaid section of the pipeline or passageway and effecting the cure ofsame, the core tube being a flexible unitary continuous hollow tube ofsufficient rigidity to support the air pressure and sufficientlybendable to enable it to bend round curves and corners around which theassembly must pass in travelling along the pipeline or passageway tosaid section with the bladder deflated during the said transportation,and the bladder and lining tube being folded to a collapsed conditionand held in such condition by temporary holding means which releasetheir hold upon the bladder when inflated and allows the liquid flowingmedium, normally accommodated by the pipeline, to continue to flowthrough the core while the assembly is being inserted and curing of thelength of the lining tube is taking place.
 2. A method according toclaim 1, wherein the assembly is carried by a transporter in the form ofa hammock having pull ropes at opposite ends thereof by which theassembly and hammock are moved into position into the pipeline orpassageway.
 3. The method of claim 1, wherein the bladder is defined bya length of inflatable tubular material turned in upon itself withadjacent free ends connected to one end of the core.
 4. The method ofclaim 3, including the steps of curing the resin and removing theassembly by pulling the assembly away from the cured liner so as toinvert the bladder as it is withdrawn from the pipeline or passageway.5. An assembly for introduction into a pipeline or passageway and forthe application to a section of said pipeline or passageway of a "curedin place" lining tube, said assembly comprising a flexible unitaryhollow core tube having at least one aperture and an annular inflatablebladder surrounding said core and aperture, said core tube being ofsufficient rigidity to support the bladder when inflated withoutcollapse of the core tube and also being sufficiently bendable to enableit to bend round curves in the pipeline or passageway into which it isinserted, an annular inflatable bladder surrounding said core, whereinthe bladder is defined by a length of inflatable tubular material turnedin upon itself to form an inner side and an outer side, and the adjacentfree ends of the inner and outer sides are connected at one end to thecore tube on opposite sides of the aperture enabling the insertion ofair under pressure in order to inflate the bladder.
 6. A method ofproviding an assembly whereby a section of a pipeline or passageway maybe lined by a "cured in place" lining system wherein a length of liningtube impregnated with synthetic resin is arranged end to end with anannular inflation bladder tube, which in turn is laid end to end with acore pipe to which the inflation tube is attached, and wherein theinflation tube is everted into the lining tube by pushing the core tubeinto the centre of the inflation tube so that in the final assembly theinflation tube surrounds the core tube and the lining tube surrounds theinflation tube, followed by deflation of the inflation tube to form theassembly for insertion in the pipeline or passageway.
 7. A methodaccording to claim 6 wherein the core tube is provided with enlargedends to prevent the lining tube from rolling off either end of the coretube.
 8. A method for lining a section of a pipeline or passageway witha cured in place liner segment, comprising:placing a resin impregnatedliner segment on an apparatus having a continuous unitary flexiblehollow tubular core with an aperture and an inflatable bladder ofmaterial turned in upon itself with adjacent free ends connected to thecore on opposite sides of the aperture; collapsing the liner about thebladder; applying temporary holding means to restrain the liner in acollapsed condition to form a lining assembly; introducing the liningassembly into the pipeline at the location to be repaired; applyingfluid pressure to the bladder through the aperture to inflate thebladder and liner and release the holding means; continuing to applyfluid pressure until the resin cures; removing the fluid pressure fromthe bladder; and removing the apparatus from the pipeline.
 9. The methodof claim 8, wherein the bladder is everted as it is removed from thepipeline.
 10. A device for lining a section of a pipeline or passagewaywith a cured in place liner segment, comprising:a core of a continuousunitary flexible hollow tubular member having an aperture; an inflatablebladder defined by a length of material turned in upon itself to form aninner side and an outer side with adjacent free ends connected at oneend to the core on opposite sides of the aperture; a liner segmentimpregnated with a curable resin and disposed about the bladder, theliner segment in a collapsed form and temporary holding means fortemporary holding the liner in the collapsed form about the core; andpressure means for providing fluid pressure to the interior of thebladder via the aperture; whereby upon pressurizing the bladder, thetemporary holding means are released and the bladder expands the linersegment against the inner wall of the pipeline and allows the resin tocure for repair of the pipeline and allows the continuous flow of liquidmedium through the core tubular member while the device is beinginserted and the inflatable bladder is pressurized while the linersegment is being cured.
 11. The device for lining a section of apipeline or passageway of claim 10, further including transported meansfor moving the device into position in the pipeline or passageway. 12.The device for lining a section of pipeline or passageway of claim 10wherein the core tubular member has a longitudinal lumen which allowsthe continuous flow of liquid medium through the core tubular memberwhile the device is being inserted and the inflatable bladder ispressurized while the liner segment is being cured.